Beyond pollination: diversity of secretory structures during flower development in different legume lineages

Abstract

Floral secretory structures are usually associated with the attraction of pollinators, but may also play an important role in the mechanisms of plant protection. Th is study aimed to show the diversity of secretory structures present in the developing fl owers of 15 legume species belonging to diff erent clades and to associate them with functions other than the pollinator attraction. Buds, fl owers and developing axis of infl orescence were processed for surface, histological, and ultrastructural analyses. Th e species investigated displayed a wide diversity of secretory structures in developing fl owers such as phenolic cells and/or tissues, mucilaginous cells, secretory cavities, secretory trichomes and colleters. Each type of secretory structure exhibited variation in morphology and location in the fl ower and/or axis of infl orescence depending on the species. Special mucilage cells, secretory cavities, secretory trichomes and colleters have great potential for comparative morphological studies due to their diversity of forms or restricted occurrence to certain taxa, contributing to a more robust morphological data base for the new clades emerging in Leguminosae. Th e scarcity of reports about fl oral secretory structures of Leguminosae seems to be more related to defi cient sampling than to the absence of such structures in the group, which highlights the need for further investigation.

More than Scales: Evidence for the Production and Exudation of Mucilage by the Peltate Trichomes of Tillandsia cyanea (Bromeliaceae: Tillandsioideae)

“…The subsequent loss of protoplasts in the wing portion establishes that secretory activity takes place exclusively during the expansion of inflorescence parts (i.e., young bracts). The association between some plant secretions and juvenile organs is common [ 38 , 45 , 46 , 49 , 50 ] and was previously reported for the reproductive and vegetative axis of A. blanchetiana [ 16 , 35 ].…”

Unveiling foliar secreting sites and secretion composition in the legume tree Swartzia flaemingii Raddi

“…Legume species exhibit a remarkable diversity of secretory structures that assume essential roles in the plant's interactions with its environment and other organisms. [31][32][33][34][35] This diversity pertains to both the morphological types and their distribution throughout the plant's structure, as well as the chemical composition of the secretions. [29,[36][37][38] In this context, examining secretory structures in a legume species like S. flaemingii offers insights into fascinating plant adaptations and presents secondary applications across multiple disciplines, underscoring their potential benefits for diverse applied uses.…”

“…Mucilage cells have also been identified in the leaves of S. flaemingii, which is a significant finding, particularly considering that the majority of documented instances of mucilage cells within the family are found in seeds, where they frequently compose the testa or endosperm. [44] The storage of mucilage within the inner periclinal wall of cells, as observed in S. flaemingii, has been scarcely reported in the literature, [45] previously noted only in sepals of Mimosa lewisii Barneby (Fabaceae), [34] as well as in sepals of Anisophyllea disticha Baill., Polygonanthus amazonicus Ducke (Anisophylleaceae), and Gillbeea adenopetala F. Muell. (Cunoniaceae).…”

“…This arrangement implies a protective role, likely to avoid photodamage and excessive water loss through transpiration. [34,37] The presence of laticifers discovered in the leaflets of S. flaemingii is an uncommon occurrence within the Fabaceae and merits special attention. Instances of laticifers in this speciesrich legume family, which comprises approximately 20,000 species, are scarcely documented in the literature.…”

Glandular trichomes of medicinal plants: types, separation and purification, biological activities

“…They are mainly distributed in the stems, leaves, flowers, and other parts of plants and can sometimes be seen in seeds, fruits, sepals, and petioles. They are more common in medicinal plants of Lamiaceae (Maurya et al 2019), Solanaceae (Bergau et al 2016), Asteraceae (Muravnik et al 2016), and Fabaceae (Barros et al 2017).…”